RIPON (CBS13) — A fourth child has been diagnosed with cancer at a San Joaquin County elementary school, and parents believe it’s because of radiation caused by a cell phone tower.

The towers are spread throughout the community, but it’s this particular one that parents say needs to go.

“We had a doctor tell us that it’s 100 percent environmental, the kind of tumor that he has,” said Monica Ferrulli.

Her son Mason was the second child to be diagnosed with cancer in just three years at Weston Elementary. He was 10-years-old and walked by this cell phone tower daily.

“It’s indescribable, it’s really tough,” she said.

“It’s one of the hardest things that I’ve been through,” said Joe Prime.

Prime’s son Kyle was the first, diagnosed with kidney cancer in 2016. And two more kids were diagnosed this year.

“It just seems like coincidence is no longer a reason for all this illness,” Prime said.

They believe it’s this cell phone tower that’s harming their kids.

“Kids shouldn’t be guinea pigs and we shouldn’t be taking chances with the children’s lives,” Prime said.

The district has had several tests done saying the tower is safe and meets federal regulations. But some families weren’t convinced and hired an expert.

“I wouldn’t send my kids there at all, it absolutely is dangerous,” said Eric Windheim, an electromagnetic radiation specialist. “Children are still developing and their cells are still being divided. It’s the worst possible time in their life to be exposed.”

He says it’s not just a cell tower, it also transmits wireless frequencies.

“Instead of only going 300 yards like regular Wi-Fi, Y-Max can go 30 miles,” he said.

Parents want the mast removed, but the district won’t budge. Parents say the district gets a kickback of $2,000 a month to have the tower for a telephone company, but the district so far has not commented.

“It’s a real disappointment that it’s taking moms of sick children and dads of sick children to come out and say something needs to be done,” Prime said.

Ferrulli’s son Mason has also since relapsed and is undergoing brain cancer treatments while a fourth child from has recently been diagnosed and taken out of school.

They say it’s not just a battle now for their children, but a fight these parents say they won’t give up.

“There’s a lot of kids that we love that still go to the school, so we are fighting for them,” Ferrulli said.

The district sent out a letter to parents saying that the electric magnetic frequencies are far below federal standards and have completed a thorough investigation and do not have any plans of removing the cell phone tower on campus.